1. Field of the Invention
This invention relates to a method of making a golf club head, more particularly to a method in which a striking plate is brazed to an open end of a casing of a golf club head.
2. Description of the Related Art
As more and more people like playing golf, either for pleasure or for physical exercise, the prior art have suggested various types of golf clubs to meet the increasing demand therefor. FIG. 1 shows a golf club head which includes a casing 10 and a striking panel 11. The casing 10 has an opening 12 covered by the striking panel 11 which is slightly greater than the opening. A rib 13 projects forwardly from an edge of the casing 10 which confines the opening 12 and extends around the opening 12 to engage a groove 14 which is formed in a rear surface of the striking panel 11 along the periphery of the striking panel 11. A welding layer 15 is provided between the surfaces of the striking panel 11 and the casing 10. The welding layer 15 is formed between the joint surfaces of the casing 10 and the striking panel 11 by melting a brazing material between the joint surfaces. The striking panel 11 and the casing 10 are coupled together after the brazing material is cooled.
Although the interengagement of the rib 13 and the groove 14 can increase the contact surface areas between the casing and the striking panel 11, as the brazing material is pre-arranged only at the edge of the opening 12 of the casing 10, the amount thereof is limited by the length of the edge of the opening 12. If the amount of the brazing material is insufficient, the bonding effect of the welding layer between the casing 10 and the striking panel 11 will be reduced.
During fabrication, the brazing material is placed along the edge of the opening 12 of the casing 10 before the striking panel 11 is attached to the casing 10. When the striking panel 11 is attached to the casing 10 to cause the groove 14 to engage the rib 13, the brazing material is squeezed between the groove 14 and the rib 13. When the brazing material is melted by heat, it oozes outward from the clearance between the groove 14 and the rib 13 and is solidified at the outer surfaces of the striking panel 11 and the casing 10. In order to remove the brazing material solidified at the outer surfaces, the striking panel 11 and the casing 10 must be subjected to manual or mechanical surface treating processes, such as grinding and/or polishing. The manufacturing process as such is laborious and time-consuming due to the need for surface treatment.
FIG. 2 shows another conventional golf club head which includes a metal casing 20 and a striking panel 21 as shown in FIG. 2. The casing 20 is formed with a recess 22 and a shoulder 23 to seat the striking panel 21 thereon, and the striking panel 21 is formed with a groove 24 at an outer edge thereof to engage a rib 25 formed on an inner surface of the casing 20 and extending around the opening thereof. The rib 25 is formed by softening and deforming a portion of the casing 20 adjacent the opening of the casing 20. The striking panel 21 is fixed to the casing 20 by brazing. This conventional golf club head also encounters a problem in that the brazing material oozes out and stains the outer surfaces of the casing 20 and the striking panel 21 during manufacture.
On the other hand, while the interlocking of the rib 25 and the groove 24 increases the firmness of the joint between the striking panel 21 and the casing 20, it is required that the rib 25 be formed at an accurate position so as to precisely mate with the groove 24 of the striking panel 21. Since the rib 25 is formed by heating and deforming a portion of the casing 20 proximate to the position of the groove 24 after the striking panel 21 is attached to the casing 20, once the striking panel 21 is attached, the groove 24 is covered by the casing 20 so that it is difficult to determine the exact position of the groove 24. Therefore, difficulties are encountered in processing the casing 20 to form the rib 25 at an accurate position relative to the groove 24. Unless the casing 20 is provided with a mark or measurement to indicate the position where the rib 25 is to be provided, it is impossible to form the rib 25 at an accurate position that permits the rib 25 to mate precisely with the groove 24.
Referring to FIG. 3, in a conventional method for coupling a golf club head casing and a striking plate, before the striking plate 30 is placed in a recess 32 of a casing 31, a brazing material 34 is put on a shoulder face 33 formed at the recess 32. Thereafter, the striking plate 30 is inserted into the recess 32 so that the brazing material 34 is pressed between the striking plate 30 and the shoulder face 33. When the striking plate 30 and the casing 31 are heated under vacuum, the brazing material 34 melts and fills the space between the casing 31 and the striking plate 30, thereby welding the striking plate 30 to the casing 31.
In the aforesaid method, the casing 31, the striking plate 30 and the brazing material 34 have different melting points, and the brazing material 34 which has the lowest melting point is melted to interconnect the casing 31 and the striking plate 30. However, since the brazing material 34 is in a powder form, when the brazing material 34 melts, the volume thereof contracts so that the brazing material 34 cannot fill the clearance between the joint surfaces of the casing 31 and the striking plate 30 completely. This results in voids between the joint surfaces of the striking plate 30 and the casing 31, thereby reducing the binding strength therebetween, and adversely affecting the stability of the golf club head.
In order to address the aforesaid problem arising from the contraction of the brazing material, an attempt has been made by increasing the amount of the brazing material 34. However, when the amount of the brazing material 34 is increased, the thickness of the brazing material 34 between the surfaces of the casing 31 and the striking plate 30 is increased, thereby enlarging the distance between the joint surfaces of the casing 31 and the striking plate 30. Therefore, if the amount of the brazing material 34 is increased too much, the binding strength can also be reduced. In addition, the brazing material can be wasted. It is a difficult task to balance the amount of the brazing material and the binding strength.
Furthermore, after the striking plate 30 is placed in the recess 32 and is pressed against the brazing material 34 which has been placed on the shoulder face 33 within the recess 32, even if voids are formed between the shoulder surface 33 and the striking plate 30 because of the insufficient amount of the brazing material 34, it is impossible to add the brazing material 34 to the voids by removing the striking plate 30 from the casing 31. In addition, during the manufacturing process, it is not easy to realize the presence of such voids in the products. Therefore, the aforesaid method cannot be relied upon to produce good quality products.